Apparatus and method for supporting a collar region of a blast hole during drilling

This patent application is the U.S. National Phase of PCT/AU2022/051166, filed Sep. 29, 2022, which designates the U.S. and which and claims priority under 35 U.S.C. § 119(a) to Australian Patent Application No. 2021903123, filed Sep. 29, 2021, and to Australian Patent Application No. 2021904057, filed Dec. 14, 2021.

The present invention relates to the field of blast hole drilling, particularly although not exclusively in blasting operations for mining and quarrying.

Bench blasting is a process that involves drilling holes into rock to depths of up to 50 metres or more. Blast holes are typically drilled using rotary or percussive drilling equipment and techniques. The holes are then charged with an explosive and the minerals and rocks are blasted and fragmented for subsequent removal by excavators for further processing.

Significant quantities of loose rock fragments, or “preconditioned” material, can remain on the bench from the sub-drilled region after achieving the Reduced Level (RL). A preconditioned layer depth of up to 4 metres or more can improve the efficiency of the comminution process by maximising the volume of fine fragmentation that results from the subsequent blasting operation.

Drilling platforms used for drilling blast holes come in different forms and are adapted for different purposes. Smaller surface drilling platforms that are typically used for drilling bore holes of between about 89 to 165 millimetres in diameter, are commonly referred to as “crawler drilling rigs”. Crawler drilling rigs are characterised by including a tracked platform with a hydraulic arm and a drilling mast attached to the end of the arm. The arm is adapted to tilt, lift and lower the mast and to locate a supporting foot of the mast on the bench surface at a location at which a bore hole is to be drilled.

Larger surface drilling platforms that are typically used for drilling bore holes of between about 165 to 351 millimetres in diameter, are commonly referred to as “platform drilling rigs”. Platform drilling rigs are characterised by including a tracked platform with a drilling mast located in a fixed, vertical position relative to the platform. Locating the mast on the bench surface at a location at which a bore hole is to be drilled requires repositioning the entire platform via operation of driven tracks.

Drilling bore holes through a preconditioned layer presents a problem of loose rock fragments in the preconditioned layer falling or collapsing into the bore hole during drilling or after drilling. Applicant's patent application WO2019014716 discloses a collar support apparatus for preventing surrounding loose rock fragments from falling or collapsing into a blast hole. The apparatus includes a normally flat flexible sheet that is formed into a curved form to define a longitudinal passage and is then inserted into the open end of a blast hole. The curved sheet closely faces an internal surface of the blast hole and forms a barrier preventing surrounding loose rock fragments from falling or collapsing into the open end of the blast hole.

Drilling platforms can or may have guard cages or other physical barriers provided around the bottom of the mast as a safety measure. Accordingly, in order to access the bore hole to insert a collar support apparatus, such as the flexible sheet of Applicant's patent application WO2019014716, the mast or the entire drilling platform may have to be cleared from the open end of the blast hole to enable a worker to insert such an apparatus into the bore hole.

After the bore hole is drilled before the mast or drilling platform is cleared from the blast hole and the flexible sheet apparatus is inserted, a substantial amount of surrounding loose rock fragments in the preconditioned layer may have fallen or collapsed into the blast hole. Accordingly, a need exists for a drilling system that minimises any chance for loose rock fragments from the preconditioned layer to collapse into the bore hole during and after drilling and until the mast or the drilling platform is cleared and a collar support apparatus is deployed such as the flexible sheet apparatus described above.

Also, there exists a need for a drilling system that supports the internal surface of the blast hole in the collar region through the preconditioned layer during the drilling operation and that is practical and efficient to use with mobile drilling platforms on a blasting bench.

Any discussion of background art throughout the specification should in no way be considered as an admission that any of the documents or other material referred to was published, known or forms part of the common general knowledge.

Accordingly, in one aspect, the invention provides a bore hole drilling system including: a mobile bore hole drilling platform including a mast disposed on the platform including a support for a drill string; a tube member for locating within the collar region of a bore hole and including an internal longitudinal passage for receiving a drill string therethrough and an external surface for facing outwardly against a wall of the bore hole; a coupling mechanism that is configured to couple and decouple the tube member and the drilling platform when the tube member is located coaxially within the collar region of the bore hole and substantially axially aligned with the drill string and/or the mast; wherein the coupling mechanism includes a support body movably connected to the drilling platform and coupling elements associated with the support body and the tube member, wherein the support body is movable vertically relative to the drilling platform and/or the mast for positioning the coupling elements of the support body and the tube member relative to each other for engagement to thereby couple the support body and the tube member.

Embodiments of the invention are advantageous in that they provide a bore hole drilling system that supports the internal surface of a blast hole in the collar region through a preconditioned layer during the drilling operation. Embodiments of the invention are advantageous in that they provide a bore hole drilling system that allows for coupling and decoupling the tube member and the drilling platform when the tube member is located coaxially within the collar region of the bore hole and substantially axially aligned with the drill string and/or the mast. Once decoupled, it is possible to access the opening at the top of the tube member in the bore hole to insert a collar support apparatus, such as the flexible sheet of Applicant's patent application WO2019014716. Some embodiments of the invention are advantageous in that they provide a bore hole drilling system that allows guard cages or other physical barriers provided around the bottom of the mast to be cleared from the open end of the blast hole to enable a worker to insert a collar support apparatus into the bore hole.

Embodiments of the drilling platform include various types of mobile drilling platforms comprising a mobile, tracked platform comprising a drill mast supporting a drill string and accompanying rotary and/or percussion air blast drilling apparatus. In some embodiments, such mobile drilling platforms include smaller surface drilling platforms that are typically used for drilling bore holes of between about 89 to 165 millimetres in diameter, commonly referred to as “crawler drilling rigs” and produced by manufacturers such as Sandvik, Epiroc, Komatsu and Caterpillar. In other embodiments, such mobile drilling platforms include larger surface drilling platforms that are typically used for drilling bore holes of between about 165 to 351 millimetres in diameter, commonly referred to as “platform drilling rigs” produced by manufacturers such as Sandvik, Epiroc, Komatsu and Caterpillar.

In another aspect, the invention includes a coupling mechanism that is configured to couple and decouple a tube member and a drilling platform when the tube member is axially aligned with the drill string, the coupling mechanism including a support body for connection to the drilling platform and coupling elements associated with the support body and the tube member, wherein the support body is movable vertically relative to the drilling platform for positioning the coupling elements of the support body and the tube member relative to each other for engagement to thereby couple the support body and the tube member.

In embodiments, the coupling mechanism is configured to couple and decouple the tube member and the drilling platform when the tube member is substantially axially aligned with the drill string and/or the mast.

In embodiments, decoupling occurs when the tube member is axially aligned with the drill string and/or the mast whereby the opening in the top of the tube member can be cleared for insertion of a collar support apparatus into the longitudinal internal passage of the tube member.

Advantageously, after decoupling the drilling platform can be translated horizontally relative to the bore hole to allow any guard cages or other physical barriers provided around the bottom of the mast to be cleared from the open end of the guide tube to enable an operator to insert a collar support apparatus therein.

In embodiments the support body is movable vertically relative to the drilling platform and/or the mast for positioning the coupling elements of the support body and the tube member relative to each other for engagement to thereby couple the support body and the tube member located within the collar region of the bore hole.

In embodiments the vertical movement of the support body relative to the drilling platform or the mast, at least in part, moves the coupling elements of the support body and the tube member into and out of engagement to thereby couple and decouple the support body and the tube member located within the collar region of the bore hole.

Preferably, the coupling elements of the support body are configured to engage the coupling elements of the tube member with, at least in part, downwards axial movement of the support body relative to the tube member and to disengage, at least in part, with upwards axial movement of the support body relative to the tube member located within the collar region of the bore hole.

In embodiments the support body includes a male or a female coupling zone and the tube member includes the other one of a male or a female coupling zone, wherein the male coupling zone is adapted to be received within the female coupling zone.

In embodiments the coupling elements include a movable latch member and a static member.

Preferably, the coupling elements include one or more movable latch members that are movably connected to the support body or the elongated tube and a static member that is fixed to the other one of the support body and the elongated tube.

In embodiments, the movable latch members are movably connected to the support body or the elongated tube and the static member is fixed to the other one of the support body and the elongated tube.

In embodiments, the movable latch member and the static member are adapted to come into and out of engagement, at least in part, upon relative inwards and outwards movement, or radial movement, of the latch member and the static member.

Preferably, a plurality of the latch members are disposed radially about a longitudinal axis of the support body.

In embodiments, the latch members each include a radially movable and axially facing abutment portion and the static member includes an axially facing ledge, wherein the abutment portion is adapted for face to face contact with the ledge upon relative radial movement of the latch member and the static member.

Preferably, each one of the latch members includes an elongated portion that is pivotally connected at one end to the support body and that is connected at an opposite end to the axially facing abutment portion, wherein the latch members are pivotable towards and away from each other for engagement and disengagement with the axially facing ledge.

In embodiments, the axially facing ledge of the static member is disposed circumferentially on the outside of the elongated tube.

Preferably, linear actuators are operable cause the latch members to pivot in opposite directions relative to the support body to cause the axially facing abutment surfaces to move radially inwardly and outwardly relative to each other.

Preferably, a linear actuator is connected between the mast and the support body and is operable for moving the support body in opposite directions aligned with a longitudinal axis of the drill string and/or the mast.

In another aspect, the invention provides a bore hole drilling system including: a mobile bore hole drilling platform including a mast disposed on the platform including a support for a drill string; a tube member for locating within the collar region of a bore hole and including an internal longitudinal passage for receiving a drill string therethrough and an external surface for facing outwardly against a wall of the bore hole; and a coupling mechanism that is configured to couple and decouple the tube member and the drilling platform when the tube member is located coaxially within the collar region of the bore hole.

In embodiments the coupling mechanism includes a support body connected to the mast of the drilling platform, the support body and the tube member including coupling elements adapted to couple and decouple the support body and the tube member.

Preferably, movement of the support body horizontally relative to the tube member located within the collar region of the bore hole positions the coupling elements of the support body and the tube member for engagement to thereby couple and decouple the support body and the tube member.

In embodiments the coupling elements of the support body are configured to engage the coupling elements of the tube member located within the collar region of the bore hole with horizontal movement of the support body in one direction relative to the elongated tube and to disengage with horizontal movement of the support body relative to the elongated tube in the opposite direction.

In embodiments the support body and the tube member include first and second horizontally spaced apart co-operable pairs of coupling elements adapted to releasably couple together the support body and the tube member located within the collar region of the bore hole.

Preferably, the first pair of coupling elements includes a recess formed in the support body, wherein the recess is defined on laterally opposite sides by a pair of upwardly facing shoulders and an opening at one end defining a female coupling zone, and an annular downwardly facing ledge disposed on a radially outwardly facing surface of the tube member defining a male coupling zone.

In embodiments, the male coupling zone is reversibly received within the female coupling zone upon horizontal movement of the support body relative to the elongated tube located within the collar region of the bore hole.

Preferably, the second pair of coupling elements includes an upwards facing abutment surface formed in the support body and horizontally spaced apart from the recess, and a transverse member extending laterally from an upper end of the tube member and including a downwards facing abutment surface, wherein the upwards and downwards facing abutment surfaces are reversibly brought into face to face relation with each other with horizontal movement of the support body relative to the elongated tube located within the collar region of the bore hole.

In embodiments, the support body includes a transverse outlet opening for cuttings and/or bailings to exit the tube member, wherein the outlet opening is coupled to a flexible hose that in turn is coupled to a vacuum pump system to be directed to a desired location on the bench surface.

Preferably, the outlet opening is connected to a flow diverter for directing dry cuttings and/or bailings into one outlet and wet cuttings and/or bailings into another outlet.

Preferably, the flow diverter is configured to direct a sample of the bailings and/or cuttings to a sampling zone for holding a stationary sample for analysis by an analyser.

In another aspect, the invention provides a method of drilling a bore hole including:

Preferably, the method includes the ability to decouple the tube member and the drilling platform when the tube member is substantially axially aligned with the drill string.

Preferably, in the event of decoupling, the tube member and the drilling platform, the drilling platform is translated horizontally relative to the bore hole to clear the opening in the top of the collar support apparatus and the collar support apparatus is inserted therein.

In embodiments of the method, after the collar support apparatus is inserted in the tube member the drilling platform is translated horizontally relative to the bore hole to substantially axially align the drill string with the guide tube and the tube member and the drilling platform are coupled before removing the tube member from the bore hole to thereby leave behind the collar support apparatus within the bore hole.

In yet another aspect, the invention provides a method of providing a collar support apparatus into a bore hole, the method including:

The tube member and the drilling platform optionally become decoupled when the tube member is located coaxially within the collar region of the bore hole and the tube member is substantially axially aligned with the drill string.

Preferably, in the event of decoupling, the tube member and the drilling platform, the drilling platform is translated horizontally relative to the bore hole to clear the opening in the top of the collar support apparatus for the collar support apparatus to be inserted therein.